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Posts tagged with 'Signal Integrity'

When designing a PCB, part of the design process is making sure the PCB works correctly. At the very least, someone does some functional testing. But what happens if problems are found? A more detailed look at the design must be performed. And in fact, the best way to end up with a working design is to check the performance during the design process.
So if you have to choose between simulating or … Read More

Are you doing any simulation today, specifically for signal integrity issues? Many design professionals believe that simulaiton is only needed for really bleeding-edge technology. But in my recent meetings with customers, they are finding they need to simulate designs that once did not. Even on simpler consumer electronic devices, or industrial controllers, the components they need to purchase for

Over the past 16 years I’ve had the pleasure of being part of the development of HyperLynx and am excited about the latest release, HyperLynx 9.0 as we are simultaneously celebrating its 25th birthday and 10th year with Mentor Graphics. HyperLynx was founded in 1988 when cell phones were the size of a lunch box, FPGAs were just hitting the streets with a Xilinx 2064 touting 64 logic cells, VHDL and

After years of pooh-poohing AMD, Intel had to admit you could get more data throughput switching to a high-speed serial approach. Let’s say high-speed serial is in the 1 to 10 Gbps range per lane, and use PCIe as an example. This is where the benefits become irresistible and the behavior becomes unexpected according to the previous rules of layout design. The PCIe specification helps define the different

If signal integrity engineers had the power to make their jobs as easy as possible, every signal in an electronic device would have its own coaxial cable to connect driver to transmitter. But then electronics would be the size of buildings again and certainly wouldn’t fit in your pocket. So instead, we try to cram as much stuff as possible onto a little PCB and make it work at 100s and 1000s

Impedance is an important concept in many different realms of engineering. We often see it in our everyday life, especially if you’ve ever hooked up a home entertainment system. From 8-ohm speaker wire to 75-ohm coaxial cable, the right impedance is crucial to watching things explode on your TV and making sure they sound good too. Simply stated, impedance describes a relationship between voltage

When trying to design SERDES signals on board, designers often receive recommendations on placing stitching vias around differential signal vias of a channel. The purpose is to provide continuous return current path when signals switch layers, so that the discontinuity of trace impedance can be minimized. Because of the increasing board density, the issues designers are facing by following this recommendation

Yeah, I can totally see Homer Simpson designing his SERDES bus and getting frustrated by all the additional insertion loss caused by his vias, and muttering to himself, “Stupid vias…” and grumbling. And then going into the lab, looking at his failing eye diagram, and shouting “D’oh!”. Okay, well Homer Simpson probably won’t be designing any SERDES busses anytime

The whole via simulation issue is admittedly complicated, and I think really boils down to whether the vias are single-ended or differential, and at what speeds you are running. When the vias are differential, the return current is basically self-contained around the vias since they have equal but opposite signals on them. Because of this, the built-in analytical model in HyperLynx models differential

Anyone who has ever had to simulate a SERDES interface knows how long it take to run a couple hundred bits through a SPICE model. Hours. Sometimes you have to kick it off overnight. And if you want to do some solution space exploration, probably one of the main purposes for running your simulation, it could take you a whole week of sims. I mean, you could take the time that your sim is running to

To begin this series on fundamentals of signal integrity, lets start at the very beginning. Before you start doing any type of simulation or analysis, what do you have to do first, what information do you have to know? Your design probably has thousands of nets, are you going to simulate all of them?? Probably not, there’s not enough time for that and truthfully, it’s not really necessary. The first

Whether the creative juices weren’t flowing or I just didn’t make the time, I’ve been on a bit of a blogging hiatus for the last month. Hopefully the ball is rolling again with this post and I can get back to a regularly scheduled program. My last blog post was introducing the concept of being a professional. I asked some “could it…” questions at the end of the post with regards to a company

Around the Western world tomorrow, kids of all ages (include some of us adults) will be celebrating Halloween. For those of you that may not know what Halloween is, it’s a celebration that originated from an old Celtic tradition where fires were lit to ward off evil spirits on Samhain - Summer’s end. This was a special night because the people of the time believe that during this night, the separation